Update dependency sidekiq to v8

Author: renovate[bot]

Gemfile.lock

@@ -77,7 +77,7 @@ GEM
     config (5.5.2)
       deep_merge (~> 1.2, >= 1.2.1)
       ostruct
-    connection_pool (2.5.0)
+    connection_pool (2.5.3)
     crack (1.0.0)
       bigdecimal
       rexml
@@ -245,7 +245,7 @@ GEM
       ffi (~> 1.0)
     rdoc (6.11.0)
       psych (>= 4.0.0)
-    redis-client (0.23.2)
+    redis-client (0.24.0)
       connection_pool
     redlock (2.0.6)
       redis-client (>= 0.14.1, < 1.0.0)